Geological Papers. 93 



formed in one of the following ways: (a) A. sediment-laden 

 superficial stream may have plunged down a crevasse and de- 

 posited the coarser sediment in a cave or pool within the ice 

 that naturally formed near the base of the waterfall, (b) 

 They may have collected in an enlargement of pool in the 

 bottom of a channel of a superficial stream, or in a pot-hole or 

 pool in the ice where the tributary streams joined the main 

 channel, (c) They may have been formed in the tunnel of a 

 subglacial stream. 



Hillside Osars or Eskars. — These ridges are usually not 

 very high — five to twenty feet — and vary in length from fifty 

 feet t® one mile. Their direction of extent is nearly the same 

 as that of the ice flow, and, also, must be about the same as 

 the direction of the slope of the ice surface in late glacial 

 times. The sediments composing them are usually gravel and 

 sand; but in some cases there are cobblestones, boulderites, 

 and even a few boulders, all distinctly but not very much 

 water-worn. 



Isolated Kames or Short Eskars (Osars) ending in a 

 Marine Delta. — The word "isolated" is here used because 

 no other gravels can be proved to have been deposited by the 

 same glacial streams to which these are due. The field evi- 

 dence indicates that they were deposited by subglacial streams. 

 The ridges and small hills of these deposits converge into a 

 small plain of horizontally stratified matter, showing clearly 

 a horizontal transition of gravel into sand at the south. They 

 are, in fact, hillside kames. 



Isolated Osar-mounds or Massives not ending in a 

 Moraine Delta Proper. — These deposits are mesas rather 

 than ridges. They belong to the region below former sea- 

 level. They are rather level on top, somewhat uneven of 

 surface, but with no reticulated ridges or kettle-holes proper. 

 The smoothness of the surface is, probably, due to wave ac- 

 tion. These table-lands consist of sand, gravel and cobble- 

 stones mixed in alternating layers, but with no variation in 

 texture from north to south. They were probably laid down 

 in a pool w^here a superficial stream fell down a crevasse, or 

 where a subglacial stream entered a pool or lake within the 

 ice. 



Systems of Discontinuous Osars. — In this class a number 

 of short ridges, often fan-like, have been placed. They have 



